Due to disease, trauma, or congenital malformation, the ossicles of the middle ear are sometimes damaged. If this damage results in a discontinuity of bone between the tympanic membrane and the oval window, no sound conducts and hearing loss results. Some or all of these ossicles can be replaced with a small prosthesis.
The use of middle ear prosthesis for reconstructing the ossicular chain has gone through a myriad of changes over the years. Since each ear has different anatomical dimensions, the length of middle ear prosthesis varies, from 2 mm to 8 mm, on average, with each patient. The most recent trend in otology is the use of titanium prostheses. These are commonly offered as a fixed length prosthesis or an adjustable type prosthesis. The fixed length means that the prosthesis is a one piece design and has a determined length at the time of manufacture. These types of prostheses have to be stocked in the operating room and present a high volume of inventory available for each given surgery. Adjustable type prostheses are manufactured in the maximum length dimension and can be adjusted to proper length by the surgeon at the time of surgery. The advantage of the adjustable type prosthesis is that a hospital need only stock minimum levels of inventory.
The current method of adjusting these types of prosthesis is manual. The surgeon uses an instrument or fingers to slide the head of the prosthesis up or down the shaft to a determined length. Once the correct dimension is reached, the surgeon crimps the head to the shaft to create a fixed length prosthesis. This type of procedure creates two problems. The first is the adjustment process itself. It is extremely difficult to manipulate these micro-sized implants with the hands or specialty instruments. Also, during the crimping process, the head may move from the exact position the surgeon selected. The second problem is unwanted handling of a sterile implant. Because the surgeon has to adjust the length of the implant using his fingers or an instrument, contamination issues increase. There is also the possibility that the prosthesis could be bent or deformed during handling.
The present invention is directed to enhancements in delivery and adjusting for an adjustable type ossicular prosthesis.